SunTouch SlabHeat Cable Question and Answer

SlabHeat cable is a series resistance electric heating cable consisting of a polyurethane outer jacket, full coverage braided copper ground plane, ETFE insulation, and dual copper heating elements connected to a single power lead for easy single-point connection.

Where may SlabHeat be installed?

SlabHeat cable is designed to be installed in residential or commercial concrete slab, slab-on-grade, or slab-over-existing-slab interior applications only. It cannot be used for exterior applications, snow melting, or in ceilings. For exterior and snow melting applications, go to www.flooringsupplyshop.com for information on our ProMelt electric snow melting products.

What are the power requirements for SlabHeat?

SlabHeat cable is available in either 120 VAC or 240 VAC models. Multiple coils may be combined on a single control up to a maximum of 15 amps. DO NOT mix voltages on the same system if multiple cables are to be installed in an area. Never load more than 12 amps (1440 watts) on a 15-amp circuit breaker, or 15 amps (1800 watts) on a 20-amp circuit breaker. If an area requires more than 15 amps to be controlled by one thermostat, use SunStat Relay(s) to take the additional amp load.

What is the recommended wire spacing for SlabHeat?

Wire spacing for SlabHeat cable depends on the heat loss of the space and the required output from the floor. 4″ wire spacing would typically be used for sun rooms, basement slabs, bathrooms, kitchens, living areas, and baths with exterior walls. 6″ wire spacing is recommended for hallways, entry ways, and large areas with low heat loss. Please note insulation is always recommended due to high heat losses in these areas. Never place SlabHeat cable any closer than 4″ from itself or other items such as underground cable or piping to avoid overheating them. Never place SlabHeat closer than 8″ to an exterior wall.

Can the SlabHeat cable length be modified?

SlabHeat Cable must never be cut shorter to fit, and must be completely embedded in concrete in the floor. Failure to do so may result in damage to the product. If the exact size of SlabHeat Cable calculated is not available, it may be necessary to adjust the warming area(s) or select the next smaller size.

How does a SlabHeat electric radiant floor compare to a hydronic (water based) radiant floor?

In general, hydronic radiant systems require more space for infrastructure, such as added space in the floor for tubes and room in the mechanical room for a water heating appliance, pumps, valves and fittings. Hydronic systems allow for various fuel sources, such as natural gas, oil, propane, solar, or electric. SlabHeat is limited to electric. SlabHeat is simpler than hydronic, takes up less space, goes in faster and for small areas, the per square foot cost is much lower. Once the system is installed, the floors will feel wonderful regardless of the chosen approach.

Who should install SlabHeat?

To install SlabHeat, intermediate skills in electrical wiring is required. Normally the heating product may be secured in place by qualified installers. However, consider hiring an electrician to rough in the wiring, especially if it is necessary to route from the circuit breaker panel. Please be aware that local codes may require this product and/or the thermostatic control be installed or connected by an electrician.

Is SlabHeat an efficient way to heat?

Generally speaking, radiant floor heating is a more efficient way to warm a space than forced air or baseboard. Radiant systems broadcast energy at the speed of light from the floor to warm all the surfaces of the room. The air temperature stays lower so there is less heat loss through windows and air infiltration, yet comfort is greater. All the electricity used by SlabHeat is converted to useful heat. Gas appliances only convert a percentage to heat; the rest is lost up the stack. For many people, gas or oil is more economical per BTU than electricity, even considering the conversion loss. A lot depends on the price for these energy sources and how well the structure is insulated. Some power companies offer reduced rates or substantial discounts on electricity consumed during “off-peak” times. Off-peak hours are the times of day or night when the power companies usually have excess energy supply due to low demand. These “off-peak” rates can further enhance the efficiency of the SlabHeat electric radiant heating system

What controls are required for SlabHeat?

SlabHeat cables utilize our standard SunStat dual voltage (120 VAC/240 VAC) controls. The SunStat Programmable and Non-programmable use a floor sensor to provide direct floor-warming control for better comfort. SunStat controls can also sense air temperature with a floor temperature limit. If an area requires more than 15 amps to be controlled by one SunStat, SunStat Relay(s) are used to take the additional amp load. Always select controls that will meet the voltage and amperage ratings of the system and are designed for resistance heating systems.

How deep should SlabHeat be embedded?

Pour concrete over the base and SlabHeat Cable so that there is a minimum of 3/4″ of material above the heating cable. The SlabHeat Cable should be no more than 1-1/2″ to 2″ below the top finished surface of the floor. Make sure SlabHeat cable is fully embedded, as well as 2″ to 6″ of the conduit(s) enclosing the power lead and slab sensor wiring.

Are there areas where SlabHeat should not be installed?

SlabHeat cable should be installed in all interior floor areas that are to be warmed. Keep in mind heat will radiate 3″ to 4″ from the SlabHeat cable, therefore consistent coverage is important. SlabHeat should be installed within 2″ of a counter or vanity kick-space to ensure warmth in this area. Do not install SlabHeat under cabinets, fixtures or inside walls. Avoid running SlabHeat in small closets or other confined areas where excessive heat will build up. Do not install SlabHeat closer than 6″ from toilet rings to avoid possible melting of wax rings. Never cross expansion joints in a slab unless proper technique and protection steps are followed. See the SlabHeat Installation manual for detailed information on proper installation techniques.

When should I turn on the SlabHeat cable?

Allow concrete to fully cure as required by the concrete supplier, typically 28 days. Do not energize the SlabHeat Cable except to briefly test it (NO MORE than 10 minutes), as this would improperly accelerate the curing and potentially cause concrete damage.

What if I damage SlabHeat?

Repair kits are available for SlabHeat Cable. Never attempt to repair a damaged cable without a factory approved repair kit. Contact the factory for assistance.

1 comment

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